I'll try to point out some things I haven't seen in the list so far:

- https://github.com/zorgiepoo/Komet for Git/Hg/etc commit messages

- https://apps.apple.com/th/app/multi-monitor-wallpaper/id5042... for splitting a single (large) wallpaper over multiple displays

- https://proxie.app for network traffic inspection

- https://apps.apple.com/th/app/the-clock/id488764545?mt=12 for a multi timezone-aware clock

- https://apps.apple.com/th/app/patterns-the-regex-app/id42944... for quickly writing/checking Regular Expressions

- https://tableplus.com for an RDBMS client